Visible Light Catalytic Material via Z-Type Heterojunction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current g-C3N4 photocatalysts have low visible light utilization rates, high electron recombination rates, and low photocatalytic efficiency due to their single-component nature, limiting their effectiveness in environmental pollution degradation.

Innovation Solution

A visible light catalytic material comprising a conductive ceramic carrier with P-C3N4, reduced graphene oxide, and bismuth vanadate as active components, forming a Z-type heterojunction structure that enhances electron transfer and photocatalytic efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If single g-C3N4 photocatalyst is used, then visible light catalytic activity is achieved, but visible light utilization rate is low and electron recombination rate is high

Engineering Contradiction:
Improvevisible light utilization rateVSAvoidelectron recombination rate
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent applies composite materials principle by constructing a Z-type heterojunction composite photocatalyst system comprising g-C3N4, BiVO4, and reduced graphene oxide. This composite structure enables synergistic effects where g-C3N4 absorbs visible light, BiVO4 extends light absorption range and provides additional active sites, and reduced graphene oxide facilitates electron transfer. The composite architecture optimizes visible light utilization while suppressing electron recombination through efficient charge separation pathways, directly resolving the technical contradiction between light utilization and energy loss.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs reduced graphene oxide as an intermediary material that mediates electron transfer between g-C3N4 and BiVO4 components. The reduced graphene oxide acts as an electron highway, accepting electrons from g-C3N4 conduction band and transferring them to BiVO4, thereby serving as a crucial intermediary that reduces electron recombination rate while maintaining high visible light utilization. This intermediary mechanism directly addresses the contradiction by providing a dedicated electron transport pathway.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If single g-C3N4 photocatalyst is used, then photocatalytic role under visible light is achieved, but photocatalytic efficiency is low

Engineering Contradiction:
Improvephotocatalytic efficiencyVSAvoidelectron separation efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements composite materials principle by designing a tri-component Z-type heterojunction system (g-C3N4-BiVO4-reduced graphene oxide) that simultaneously enhances photocatalytic efficiency and electron separation efficiency. The g-C3N4 provides visible light absorption, BiVO4 extends spectral response and creates additional reaction sites, while reduced graphene oxide ensures efficient electron separation and transport. This composite architecture achieves high productivity through synergistic effects while maintaining reliability via optimized charge separation, resolving the contradiction between photocatalytic efficiency and electron separation efficiency.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies segmentation principle by dividing the photocatalytic system into functionally distinct segments: g-C3N4 segment for visible light absorption and initial charge generation, BiVO4 segment for extended light absorption and additional catalytic sites, and reduced graphene oxide segment for electron transport and separation. This functional segmentation allows each component to optimize its specific role, thereby achieving high overall photocatalytic efficiency while maintaining excellent electron separation efficiency through specialized functional zones.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The material exhibits improved visible light catalysis and recovery efficiencies, effectively degrading pollutants with enhanced electron transfer and stability, as demonstrated by its application in sewage treatment.

Implementation Method 1

the conductive ceramic has conductive properties and will also play a role of transferring electrons

Methodology Applied
Scientific EffectElectron conduction: Conduction (electrical)

Implementation Method 2

Both P-C 3 N 4 and BiVO 4 can be excited by visible light to generate photogenerated electrons and holes

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 3

the electrons in the conduction band of BiVO 4 will be transferred to the valence band of P-C 3 N 4 and recombined with its holes

Methodology Applied
Scientific EffectElectron transfer: Conduction (electrical)

Implementation Method 4

Photocatalysis technology can directly and effectively use solar energy to degrade pollutants in the environment

Methodology Applied
Scientific EffectPhoto-oxidation: Photo-oxidation

Data Source

PatentEP3848122B1Visible light catalytic material and preparation method and application thereof
Publication Date: 2022.08.10 NANKAI UNIV
  • EP3848122B1 patent drawingFigure 1
  • EP3848122B1 patent drawingFigure 2

AI summary

The invention provides a visible light catalytic material and a preparation method and application thereof, which belongs to the technical field of catalysts. The visible light catalytic material provided by the present invention includes a carrier and an active component supported on the surface of the carrier; the carrier is a conductive ceramic; the active component is P-C3N4, graphene oxide and bismuth vanadate; raw materials for preparing the conductive ceramics include graphene, aluminum oxide and zinc oxide. In the visible light catalytic material provided by the present invention, both P-C3N4 and BiVO4 can be excited by visible light to generate photogenerated electrons and holes, and the reducing electrons on BiVO4 are transferred to P-C3N4, and recombined with its oxidizing holes, RGO can be used as an electron transport medium to enhance the above process. The present invention uses active components of specific composition and carrier to cooperate to provide the visible light catalytic material with excellent visible light catalysis efficiency and recovery efficiency.